// Copyright 2003-2010 Christian d'Heureuse, Inventec Informatik AG, Zurich, Switzerland
package com.sjj.encode;
//www.source-code.biz, www.inventec.ch/chdh
//
//This module is multi-licensed and may be used under the terms
//of any of the following licenses:
//
//EPL, Eclipse Public License, V1.0 or later, http://www.eclipse.org/legal
//LGPL, GNU Lesser General Public License, V2.1 or later, http://www.gnu.org/licenses/lgpl.html
//GPL, GNU General Public License, V2 or later, http://www.gnu.org/licenses/gpl.html
//AL, Apache License, V2.0 or later, http://www.apache.org/licenses
//BSD, BSD License, http://www.opensource.org/licenses/bsd-license.php
//MIT, MIT License, http://www.opensource.org/licenses/MIT
//
//Please contact the author if you need another license.
//This module is provided "as is", without warranties of any kind.

/**
* A Base64 encoder/decoder.
* 
* <p>
* This class is used to encode and decode data in Base64 format as described in RFC 1521.
* <p>
* 
* Project home page: 
* <a href="http://www.source-code.biz/base64coder/java/">www.source-code.biz/base64coder/java</a><br>
* Author: Christian d'Heureuse, Inventec Informatik AG, Zurich, Switzerland<br>
* Multi-licensed: EPL / LGPL / GPL / AL / BSD / MIT.
*/
public class Base64Coder 
{
	// The line separator string of the operating system.
		private static final String systemLineSeparator = System.getProperty("line.separator");

		// Mapping table from 6-bit nibbles to Base64 characters.
		private static final char[] map1 = new char[64];
		static {
			int i = 0;
			for(char c = 'A'; c <= 'Z'; c++)
				map1[i++] = c;
			for(char c = 'a'; c <= 'z'; c++)
				map1[i++] = c;
			for(char c = '0'; c <= '9'; c++)
				map1[i++] = c;
			map1[i++] = '+';
			map1[i++] = '/';
		}

		// Mapping table from Base64 characters to 6-bit nibbles.
		private static final byte[] map2 = new byte[128];
		static {
			for(int i = 0; i < map2.length; i++)
				map2[i] = -1;
			for(int i = 0; i < 64; i++)
				map2[map1[i]] = (byte) i;
		}

		/**
		 * Encodes a string into Base64 format. No blanks or line breaks are
		 * inserted.
		 * 
		 * @param s A String to be encoded.
		 * @return A String containing the Base64 encoded data.
		 */
		public static String encodeString(String s) {
			return new String(encode(s.getBytes()));
		}

		/**
		 * Encodes a byte array into Base 64 format and breaks the output into lines
		 * of 76 characters. This method is compatible with
		 * <code>sun.misc.BASE64Encoder.encodeBuffer(byte[])</code>.
		 * 
		 * @param in An array containing the data bytes to be encoded.
		 * @return A String containing the Base64 encoded data, broken into lines.
		 */
		public static String encodeLines(byte[] in) {
			return encodeLines(in, 0, in.length, 76, systemLineSeparator);
		}

		/**
		 * Encodes a byte array into Base 64 format and breaks the output into
		 * lines.
		 * 
		 * @param in An array containing the data bytes to be encoded.
		 * @param iOff Offset of the first byte in <code>in</code> to be processed.
		 * @param iLen Number of bytes to be processed in <code>in</code>, starting at <code>iOff</code>.
		 * @param lineLen Line length for the output data. Should be a multiple of 4.
		 * @param lineSeparator The line separator to be used to separate the output lines.
		 * @return A String containing the Base64 encoded data, broken into lines.
		 */
		public static String encodeLines(byte[] in, int iOff, int iLen,
											int lineLen, String lineSeparator) {
			int blockLen = (lineLen * 3) / 4;
			if(blockLen <= 0)
				throw new IllegalArgumentException();
			int lines = (iLen + blockLen - 1) / blockLen;
			int bufLen = ((iLen + 2) / 3) * 4 + lines * lineSeparator.length();
			StringBuilder buf = new StringBuilder(bufLen);
			int ip = 0;
			while(ip < iLen) {
				int l = Math.min(iLen - ip, blockLen);
				buf.append(encode(in, iOff + ip, l));
				buf.append(lineSeparator);
				ip += l;
			}
			return buf.toString();
		}

		/**
		 * Encodes a byte array into Base64 format. No blanks or line breaks are
		 * inserted in the output.
		 * 
		 * @param in An array containing the data bytes to be encoded.
		 * @return A character array containing the Base64 encoded data.
		 */
		public static char[] encode(byte[] in) {
			return encode(in, 0, in.length);
		}

		/**
		 * Encodes a byte array into Base64 format. No blanks or line breaks are
		 * inserted in the output.
		 * 
		 * @param in An array containing the data bytes to be encoded.
		 * @param iLen Number of bytes to process in <code>in</code>.
		 * @return A character array containing the Base64 encoded data.
		 */
		public static char[] encode(byte[] in, int iLen) {
			return encode(in, 0, iLen);
		}

		/**
		 * Encodes a byte array into Base64 format. No blanks or line breaks are
		 * inserted in the output.
		 * 
		 * @param in An array containing the data bytes to be encoded.
		 * @param iOff Offset of the first byte in <code>in</code> to be processed.
		 * @param iLen Number of bytes to process in <code>in</code>, starting at <code>iOff</code>.
		 * @return A character array containing the Base64 encoded data.
		 */
		public static char[] encode(byte[] in, int iOff, int iLen) {
			int oDataLen = (iLen * 4 + 2) / 3; // output length without padding
			int oLen = ((iLen + 2) / 3) * 4; // output length including padding
			char[] out = new char[oLen];
			int ip = iOff;
			int iEnd = iOff + iLen;
			int op = 0;
			while (ip < iEnd) {
				int i0 = in[ip++] & 0xff;
				int i1 = ip < iEnd ? in[ip++] & 0xff : 0;
				int i2 = ip < iEnd ? in[ip++] & 0xff : 0;
				int o0 = i0 >>> 2;
				int o1 = ((i0 & 3) << 4) | (i1 >>> 4);
				int o2 = ((i1 & 0xf) << 2) | (i2 >>> 6);
				int o3 = i2 & 0x3F;
				out[op++] = map1[o0];
				out[op++] = map1[o1];
				out[op] = op < oDataLen ? map1[o2] : '=';
				op++;
				out[op] = op < oDataLen ? map1[o3] : '=';
				op++;
			}
			return out;
		}

		/**
		 * Decodes a string from Base64 format. No blanks or line breaks are allowed
		 * within the Base64 encoded input data.
		 * 
		 * @param s	A Base64 String to be decoded.
		 * @return A String containing the decoded data.
		 * @throws IllegalArgumentException If the input is not valid Base64 encoded data.
		 */
		public static String decodeString(String s) {
			return new String(decode(s));
		}

		/**
		 * Decodes a byte array from Base64 format and ignores line separators, tabs
		 * and blanks. CR, LF, Tab and Space characters are ignored in the input
		 * data. This method is compatible with
		 * <code>sun.misc.BASE64Decoder.decodeBuffer(String)</code>.
		 * 
		 * @param s A Base64 String to be decoded.
		 * @return An array containing the decoded data bytes.
		 * @throws IllegalArgumentException If the input is not valid Base64 encoded data.
		 */
		public static byte[] decodeLines(String s) {
			char[] buf = new char[s.length()];
			int p = 0;
			for (int ip = 0; ip < s.length(); ip++) {
				char c = s.charAt(ip);
				if (c != ' ' && c != '\r' && c != '\n' && c != '\t')
					buf[p++] = c;
			}
			return decode(buf, 0, p);
		}

		/**
		 * Decodes a byte array from Base64 format. No blanks or line breaks are
		 * allowed within the Base64 encoded input data.
		 * 
		 * @param s A Base64 String to be decoded.
		 * @return An array containing the decoded data bytes.
		 * @throws IllegalArgumentException If the input is not valid Base64 encoded data.
		 */
		public static byte[] decode(String s) {
			return decode(s.toCharArray());
		}

		/**
		 * Decodes a byte array from Base64 format. No blanks or line breaks are
		 * allowed within the Base64 encoded input data.
		 * 
		 * @param in A character array containing the Base64 encoded data.
		 * @return An array containing the decoded data bytes.
		 * @throws IllegalArgumentException If the input is not valid Base64 encoded data.
		 */
		public static byte[] decode(char[] in) {
			return decode(in, 0, in.length);
		}

		/**
		 * Decodes a byte array from Base64 format. No blanks or line breaks are
		 * allowed within the Base64 encoded input data.
		 * 
		 * @param in A character array containing the Base64 encoded data.
		 * @param iOff Offset of the first character in <code>in</code> to be processed.
		 * @param iLen Number of characters to process in <code>in</code>, starting at <code>iOff</code>.
		 * @return An array containing the decoded data bytes.
		 * @throws IllegalArgumentException If the input is not valid Base64 encoded data.
		 */
		public static byte[] decode(char[] in, int iOff, int iLen) {
			if (iLen % 4 != 0)
				throw new IllegalArgumentException(
						"Length of Base64 encoded input string is not a multiple of 4.");
			while (iLen > 0 && in[iOff + iLen - 1] == '=')
				iLen--;
			int oLen = (iLen * 3) / 4;
			byte[] out = new byte[oLen];
			int ip = iOff;
			int iEnd = iOff + iLen;
			int op = 0;
			while (ip < iEnd) {
				int i0 = in[ip++];
				int i1 = in[ip++];
				int i2 = ip < iEnd ? in[ip++] : 'A';
				int i3 = ip < iEnd ? in[ip++] : 'A';
				if (i0 > 127 || i1 > 127 || i2 > 127 || i3 > 127)
					throw new IllegalArgumentException(
							"Illegal character in Base64 encoded data.");
				int b0 = map2[i0];
				int b1 = map2[i1];
				int b2 = map2[i2];
				int b3 = map2[i3];
				if (b0 < 0 || b1 < 0 || b2 < 0 || b3 < 0)
					throw new IllegalArgumentException(
							"Illegal character in Base64 encoded data.");
				int o0 = (b0 << 2) | (b1 >>> 4);
				int o1 = ((b1 & 0xf) << 4) | (b2 >>> 2);
				int o2 = ((b2 & 3) << 6) | b3;
				out[op++] = (byte) o0;
				if (op < oLen)
					out[op++] = (byte) o1;
				if (op < oLen)
					out[op++] = (byte) o2;
			}
			return out;
		}

		// Dummy constructor.
		private Base64Coder() {
		}
}// end class Base64Coder